cardiac arrhythmias provide broad new understanding of the heart, providing novel remedies and new approaches for treatment. The new findings will be presented in a tightly integrated set of talks covering structural and molecular biology, cell biology and physiology and therapeutics and clinical approaches. The symposium will bring together a unique group with expertise in structural biology, molecular and systems physiology, and industrial approaches to target discovery and drug development. Newly identified protein structures provide insight into ion channel behavior and regulation. This work spans the behavior, structure and function of normal and disease-linked gene mutations of K+, Na+, Ca2+ , RyR and IP3R channels. In addition, macromolecular complexes have been identified and characterized and reveal how specific elements provide extraordinary local control of cardiac cellular signaling. The subcellular organization, dependent on cytoskeletal organization, has been shown to significantly contribute to the normal cell function and disease. New molecular and pharmacological approaches to treatment arise from this understanding. This meeting will present new research findings on key molecules involved in heart rhythm disturbances. Cardiovascular disease is the leading cause of death in both males and females in the United States. This meeting will explore our understanding of the functioning of the heart, at its most basic molecular level, and discuss new molecular treatments.